Comparative study of juvenility resulting from <em>in vitro</em> propagated <em>Vitis vinifera</em> L., cv. Albari&ntilde;o vines when subjected to different pruning systems

Plants of Vitis vinifera L., cv. Albariño propagated in vitro were planted on their own roots and subjected to three different pruning systems, one at high level (Crosstree cordon system), one at middle level (Sylvoz system) and one at low level (Royat cordon system). Ampelographic and ampelometric characters were studied in different organs of these vines at several periods of the vegetative cycle during the 4th and 5th year. ln the 4th year, although the vines from the Crosstree cordon system were slightly different, all of them showed very similar characteristics, such as: leaves with deep lateral sinuses, anthocyanin pigmentation of buds, and of the dorsal face of the nodes and internodes, presence of erect hairs on the young and adult leaves and, above all, on the margin of the dentation. These features were less noticeable in leaves on the Crosstree cordon system. Flowering during the 4th year was limited resulting in the production of a low number of small grape clusters. In the high cordon system, the level of f1owering was slightly better. During the 5th year, a very marked difference was observed between the vines subjected to the Crosstree high cordon pruning system and those subjected to the other two systems. In the first case, the leaves show an almost total absence of erect hairs and lateral sinuses, and the number and the size of grape clusters increase significantly. The vines from Sylvoz and cordon Royat continued practically to appear the same as the previous year and flowering continued to be almost absent